


Kill the lights

by orphan_account



Category: Undertale (Video Game)
Genre: Explicit Sexual Content, Grinding, M/M, Only small hints of papyton, Rough Oral Sex, Rough Sex, Sex Magic, soulplay
Language: English
Status: Completed
Published: 2015-11-22
Updated: 2015-11-22
Packaged: 2018-05-02 19:01:00
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,984
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5260055
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: <blockquote class="userstuff">
              <p>It was always quiet for a bit before the real feud began. The two would measure the time they had silently until Papyrus would return before turning and glaring at one another, eyes narrow slits of dangerous color, Sans’ ruling the match, glowing blue orbs emitting dangerous smoke, Mettaton holding his ground with piercing pink eyes that threatened to shoot lasers, fingers clutching the couch cushions, manicured black nails ripping the fabric, holding him back from lunging and fist fighting with the short monster.</p>
<p>This time, however, Papyrus had forgotten an ingredient and ran out of the house, heading for a different village completely. They had at least an hour to kill. Literally.</p>
            </blockquote>





	Kill the lights

**Author's Note:**

> Regret is for the weak

“ Papyrus, darling, why is it your brother is always such a soursport when I’m around,” Mettaton sighed, intertwining his fingers, laying them over his knee as he threw a casual pink metallic gaze over toward the stairs of the humble abode they were residing in. Just minutes before, Sans had walked past them, but not before flashing a dangerous blue glowing pupil in Mettaton’s direction, talking in his head and disappearing as soon as Papyrus looked over. It was, to say the least, terrifying.

The taller of the skeleton brothers raised a brow, which shouldn’t have been possible for a skeleton, but nothing in the monster world made sense, it seemed.

“ Sans? Oh, he just likes making his silly baby jokes around new people. He really isn’t that bad, seeing as he is a brother to I, The Great Papyrus!”

A mechanical whirring of laughter rumbled through the chestplate adorning Mettaton. “ I suppose you’re right.” He wasn’t actually okay with that explanation, but anything to make his darling skeleton boyfriend happy was something he was willing to give up, including his own comfort. Most times.

He’d have to get used to Sans intruding on his relationship it seems, but that proved much, much harder than he ever thought it would be.

There were plenty of times where Papyrus went to do something in the kitchen that left Sans and Mettaton alone on the couch.

It was always quiet for a bit before the real feud began. The two would measure the time they had silently until Papyrus would return before turning and glaring at one another, eyes narrow slits of dangerous color, Sans’ ruling the match, glowing blue orbs emitting dangerous smoke, Mettaton holding his ground with piercing pink eyes that threatened to shoot lasers, fingers clutching the couch cushions, manicured black nails ripping the fabric, holding him back from lunging and fist fighting with the short monster.

This time, however, Papyrus had forgotten an ingredient and ran out of the house, heading for a different village completely. They had at least an hour to kill. Literally.

The door shut and the two were instantly tangled as punches were thrown, Sans pulling the robot’s synthetic hair and yanking hard, Mettaton grabbing his shirt and shoving him back, flinging him off the couch, eyes narrowed, lips pulled up in a grimace as he watched some of the hair come with Sans, not enough to matter, but enough to send the robot into a frenzy.

Sans hit the wall and slid down, grinding his jaw bones, eyes flashing as he picked himself up and launched himself back at Mettaton, disappearing right as the robot thought he had a chance of hitting him.

Pink eyes opened wide as he looked around, spinning on heel to try and locate the skeleton he was fighting earlier. He found nothing and blinked in confusion, stance falling.

“ What in the world…”

Sans was nowhere to be seen, which made the robot feel very, very uneasy. Even as he used systems built into him to locate the monster brother of his boyfriend, he found nothing.

That was, until he saw a picture of blue floating right in front of him and had his mouth forcibly covered, muffling the sounds of surprise as he was dragged through time with Sans. The robot continued to flail until he was tossed to the floor in the new location. Judging by the smell and look of it, this was Sans’ room. 

How did he..

Mettaton looked up to see Sans standing above him, the room completely black except for the light emitting from his eye, as well as the pink hue lighting up Mettaton’s own chest and lower abdomen.

“ What’s the matter, prettyboy, wire in a knot?”

The anger returned tenfold as Mettaton picked himself back up and used as much speed as he could to knock Sans back, covering his eye with a hand, feeling the energy radiated and burning the precious metal of his palm. Thank god he couldn’t feel pain like a human.

Sans struggled and growled animalistically, wrapping his bony phalanges around the devices whirring up a storm on Mettaton’s chest, pulling and digging his offending digits into the static storm that was brewing underneath, getting shocked the entire time, but refusing the fall victim to the bursts of electricity as Mettaton himself began to jolt and writhe, growling, a hand smoothing over the ribs under the white shirt Sans always wore, gripping the bone beneath it, fingers ripping holes as he yanked on the bone, a garbled noise coming from Sans as he growled, the energy rumbling deep in his chest, licking at the fingers protruding into the space, wrapping around them and holding them in place as he shook in rage. 

The slippers had long since slipped off his bony feet and he used this advantage to kick the heart chamber in Mettaton’s armor, trying to break it open, only succeeding in cracking it slightly. The result of this was Mettaton dropping him and stumbling back, oil slipping from his mouth as he set a hand on the damaged item, hair blown completely out of the way, eyes both focused on Sans.

“ You little shit! I outta-!”

His next comment was interrupted as he was enveloped in blue magic and flung to the bed, Sans pouncing on top of him, grinning sadistically.

Mettaton laid flush against the bed, growling and spitting oil at the skeleton, flashing his teeth as he struggled at his magical bindings. Sans simply went slack for a moment as the liquid of the blackened saliva slid down his skull, dipping into his empty sockets before dripping completely off his body before the grin came back and both eyes lit up, one still blue and pulsing with magic and the other white as snow, narrowed and hiding terrible intents. 

Mettaton gulped slightly, staring up at the skeleton who definitely had his end in mind.

It wasn’t that he was afraid of dying, but to die at the hands of such a little brat would just be downright shameful.

A tongue made completely of magic and static souls glowed in Sans’ mouth and he stuck it out at Mettaton, childishly mimicking Frisk, letting some of his magic binding the robot go without noticing it.

Mettaton noticed, however, and lunged forward and tackled Sans down into the covers, kissing him roughly, all teeth and tongue, fighting to keep him in place, thighs pressed to either side of the skeleton’s shorts, soul radiating in it’s chamber, knocking at the casing as if begging to be free, pink whisps pressing through the crack, shocking Sans where it touched down.

The skeleton gasped and growled, biting the robot as they kissed harshly, hand coming up under Mettaton to caress the pink chamber, teasing the soul and causing Mettaton to shudder, hair falling back into his face as he ran his own hands under the stupid shirt the skeleton was always wearing, yanking him up by his ribs and digging his nails into the membranes, scratching them as he roughly jerked them with his palm, making sure to damage them as much as he could without breaking them, and Sans fucking loved it. 

They rolled across the covers for a bit, grinding, rubbing, and biting until Sans was once again on top, Mettaton breathless and enthralled beneath him, the fan circuits in his body damaged from the skeleton’s earlier prodding and tearing, cheeks completely flushed with pink liquid that resembled oil beneath the metallic skin.

Sans, surprisingly, wasn’t much better himself, skull flushed blue, glaring and panting down at the robot beneath him, beads of sweat running down the white bone.

The crack on the chamber that lit up Mettaton’s bottom half had expanded by now and was resembling broken plastic, fractures like lightning across the pink gem, the soul beating against the glass, begging to be free, even if its owner didn’t want it to.

Sans once again dug his bony fingers into the pink whisps, causing Mettaton to growl and muffle a moan, not wanting Sans to know just what this was doing to him. But he did, and the robot would not be getting out of this easily. 

With one quick flip of a lock, the chamber opened completely and Sans thrust his fingers in, pleased by the breathy, mechanical scream he got from Mettaton, the other male twitching and jolting in pleasure, a constant stream of curses leaving his metallic lips, panting hard. Sans dipped down and began mouthing the bundle of magic, teasing his tongue in and out of the electric cavern, leaning down as far as he possibly could, sucking and deepthroating the magical bundle. 

Mettaton was panting and whining, moaning loudly as his legs spasmed, fingers holding the blankets like a vice as he bucked up against Sans’ face, resembling more of a pornstar than a tv host, begging and pleading for something, anything. 

How pathetic.

Sans couldn’t help but snicker and Mettaton glared, face flushed as he lifted his legs, albeit with a great amount of difficulty, and forced Sans back with the heel of his pink boots, flipping the chamber back shut, despite the viscous liquid bubbling in the duct from the intrusive attention that it was getting only seconds prior.

Sans snickered again, licking up the excess liquid that bubbled from the soul in his mouth, putting on a show of swallowing it and playing with the remains of it on his blue tongue, the pink juice extremely vibrant on his own soul’s magic, sitting back on his bony haunches, as if daring the robot to make his next move.

He didn’t have to wait long until those same legs that had pushed him away dragged him back into place, holding him there as the robot sat up, using his arms to keep the skeleton still as he made quick work of the short monster’s mandible and clavicle, dragging his rubbery tongue over the sensitive bones, grinning wickedly as the skeleton began to shake, struggling against the robot parts binding him, too caught up in the metallic limbs to use his own magic, tossing and turning, trying to escape the tongue that was now being dragged down his sternum. 

All the while Mettaton was humming, licking and sucking the bones to get a reaction before biting hard to leave teeth marks in the membranes, forever a reminder of what was happening. 

Not that Sans would ever want to forget this.

But he wouldn’t go down without a fight.

Sans pushed himself down on his knees and straddled the robot’s waist, yanking him closer with his legs as he pressed his clothed sacrum onto the heart chamber again. 

The pink whisps sent shocks of electricity haywire, driving Mettaton mad enough to actually reach down and undo the latch himself, the liquid from before seeping into the fabric of Sans’ shorts as the skeleton ground down against the soul, gasping and panting as he clawed at Mettaton’s arms, stimulated from two objects, a tongue and a literal soul vibrator, twisting and turning, drooling as he squirmed. 

Mettaton loosened his grip just enough to harshly kiss the skeleton again, panting and groaning as they both got closer, synthetic hair plastered to his metallic skin as he continued to kiss and abuse the skeleton, not much better himself as Sans continuously fingered the glowing pink entity of energy in a rapid thrusting movement, the curves and ridges in his boney fingers digging and bending the soul magic this way and that as it tried to get used to it, pink liquid sliding down his wrist as he dug them in even deeper, scissoring and curling his digits to make sure the magic never settled in one place for long. Mettaton was once again writhing and panting like a pornstar, holding Sans in place, pelvis pressed right on top of the chamber as payback as the skeleton choked on his breath, sweat dripping from his skull, mouth lolling open as he struggled to get out of place, but to no avail, gritting his teeth.

“F-fu-fuck..”

Mettaton smirked.

Sans headbutted him in the face for it and was once again held in place, throwing his head back in a broken sound of pleasure,face burning in shame, breathing heavily.

”F-Fuck!”

” N-Naughty, na-naughty,” The mechanic voice whirred snidely, the tone punctuated by malfunctioning voice files that resembled heavy breathing and moaning.

Sans growled and kicked him and Mettaton hit him right back, leaning in and kissing him again to shut him up, met with no resistance this time. Good.

They were both stuck in heaven and hell at the same time, still trying to fight, but getting off on the thought of making the other beg for release as well. It was exhilarating and wrong, which made it that much more fun.

Finally, the last string of control left in them snapped and the two lost it.

Mettaton shook and whined pathetically, the voice control boxes in him both working and malfunctioning at a neck break pace, still trying to glare and grit his teeth as he rode out his high, making sure to buck and grind against Sans who was also riding out a high and groaning, bed squeaking with every bit of movement between the two, panting and moaning as they both finally came out of it, literally falling back from each other. The magic that Sans was using was completely drained by now and the tongue he had been using quite profusely was gone, the only light in the room now Mettaton’s heart chamber, which was slowly closed as the robot tried to catch his own breath, sprawled across the covers, damp and sticky from the activities that took place.

The two slowly sat up, both stained from the activities, blinking at one another. How the hell…

“ What..the…fuck…”

They just stared at one another.

“ Well, that..”

“ Shit…Do you think Pap’ll notice?”

As if on cue, a loud voice bellowed from downstairs.

“ The Great Papyrus has returned! But, it seems that no is here to meet him! Why is no one here to meet him? Did The Great Papyrus miss something?”

There was a crashing from upstairs as Mettaton shoved Sans away. He fixed his hair as much as he could, running a finger over his lips, feeling for the dents that were now in them from his little rendezvous with Sans.

The other partner in their deed was wearing a shit-eating grin as he heard footsteps in the living room, along with the shaking of bones that only Papyrus could make.

Flicking one last glance toward Sans, Mettaton blew a kiss. “ Well, I suppose it’s time I be off, darling~” Mettaton purred as he walked toward the door, stopping short. “ Although…” He turned once more, pink eyes piercing into white, a hand on his hip, sly smile on his face. “I won’t hesitate to take you up on an offer like this in the future, Sans dear. Ta ta for now~” With that, the robot cleaned himself off quickly and left the room, going to meet his boyfriend.

Papyrus looked up at the sound of footsteps, lighting up instantly and rushing up the stairs.

“ Darling, I was hoping to surprise you~! I’m so very sorry I wasn’t here to meet you,” the robot apologized, hugging the taller skeleton brother close.

“ Oh, it is nothing, Mettaton! I was simply…Testing you guys! Yes, The Great Papyrus was testing Sans and Mettaton to see if they would be stealthy enough to detect his presence! You passed, congratulations!”

Mettaton chuckled slightly, pressing a kiss to Papyrus’ cheek. “ You’re absolutely precious, you know that?”

“ OH, stop it!” Papyrus giggled and swatted lightly at his boyfriend to rid himself of the tight affection. “ Would you tell Sans to come down here? The spaghetti is almost finished! One more ingredient and it will be…INCREDIBLE! ABSOLUTELY PERFECT! THE BEST SPAGHETTI ANYONE HAS EVER MADE IN THE ENTIRE MONSTER REALM!”

Mettaton winced slightly at the verboseness of the skeleton. “ Of course, darling, I’ll be right back.”

He waited for Papyrus to flee the scene before knocking on Sans’ door. “ Sans, your brother has made food and would like you to go downstairs and eat it.”

“ Nah.”

“ Sans.”

“ Nope.”

“ Sans..”

“ Naaaaah.”

“ Sans! Your brother wants you downstairs to eat,” Mettaton said through clenched teeth.

There was shuffling and the shorter skeleton came to the door. “ Sorry, I’m still full from your soul,” he snickered, showing off his glowing tongue to Mettaton again before shutting the door in his face.

“ Why you little-!”

Papyrus’ voice interrupted him. “ THE FOOD IS DONE! PLEASE, COME JOIN ME FOR A GLORIOUS FEAST OF NOODLES AND SAUCE, YOU TWO!”

Heaving a mechanical whirring sigh, Mettaton cooled himself down before heading back downstairs, eventually joined by Sans who kicked him under the table as they ate. 

Papyrus was oblivious and ate happily.

“ It is so nice to see you two getting along!”

“ Yeah, getting along,” Mettaton repeated, glaring at Sans, who grinned cheekily as they had a kicking fight under the table.

Suddenly, Papyrus stood, his food being flung off the table in his haste, hands slamming down on the wood as he spoke, filled with determination.“ That ingredient may be what has made this dish DELICIOUS! I should go get more for it when I make it again! The way to it is so lovely, I have no problem making the journey many, many times,” Papyrus exclaimed.

Sans smiled genuinely at his brother, patting his hand. “ Sounds amazing, bro.”

“ I shall go get more now! For I am wanting to make the spaghetti again! It will be the BEST spaghetti, even better than the LAST SPAGHETTI!”

Without another word he fled the house and Sans looked at Mettaton slyly. “ Ready for round two, bolthead?”

“ Bring it, numbskull.”

**Author's Note:**

> If you can find me on tumblr, I'm always taking suggestionssssss~  
> No cheating and posting a link to it though, that's just not fair~


End file.
